Study settles debate over giving stroke patients routine oxygen

A national trial involving more than 8,000 patients has revealed that giving oxygen to stroke victims makes no difference to their recovery or chances of survival.

The study was led by Keele University’s stroke specialist Professor Christine Roffe, along with North Staffordshire Combined Healthcare NHS Trust and researchers from the University of Oxford and the University of Birmingham, and was funded by the National Institute for Health Research.

Every year 152,000 people in the UK suffer a stroke. It is the fourth-largest cause of death in the UK, and half of all stroke survivors have a disability. During and after a stroke, blood supply to part of the brain is reduced, leading to a lack of oxygen.

The Stoke Oxygen Study looked at whether or not giving patients oxygen soon after their stroke could prevent further brain damage and reduce the risk of disability or even death.

Professor Roffe commented: “When a stroke happens either due to a blood clot or a brain haemorrhage, part of the brain dies because it’s being starved of oxygen, and other parts of the brain are unstable and vulnerable to low oxygen levels. Patients with stroke often have breathing problems leading to low oxygen levels. Our study provided low-dose oxygen to keep the patient’s oxygen levels within the normal range to test whether this would help to maintain brain function and help recovery, but we found that this intervention did not make a real difference.

“At present, it is common when a stroke patient first receives care that they are given an oxygen mask, but our results provide clear and unambiguous evidence that patients admitted to hospital with a stroke do not need routine prophylactic oxygen treatment.

“It remains important to monitor oxygen levels but it is not necessary to give patients oxygen routinely after a stroke — it did not improve patients’ brain function, level of disability, quality of life or chances of survival.”

During the nine-year study three treatments were used, including providing continuous oxygen (day and night) for three days, overnight oxygen supply only for three nights, and no routine oxygen supply for three nights (unless required). The results found that providing routine oxygen did not improve functional outcome in any patients, and there was still no difference in results after 90 days.

The research is one of the largest stroke studies conducted in the UK and over half of all hospitals admitting stroke patients in England took part. The findings will now help clinicians to better understand how stroke patients should be treated when they first present at hospital.

Professor Roffe added: “While we have shown that giving oxygen routinely to all stroke patients makes no difference, we also know that stroke patients whose oxygen levels fall below normal levels recover less well. Low oxygen levels are caused by underlying airway, lung and heart problems, with the most common cause being pneumonia, therefore we now believe that it may be more important to address the underlying cause rather than just to treat the hypoxia by administering oxygen.”

Professor Roffe and her team are now focusing their research efforts on ways to prevent pneumonia.